LCM problem, Help

My 04 is saying check LCM....all lights on tractor work except dash. Now on the trailer I have marker lights at top all over Trlr....I have no marker lights on bottom of Trlr. If I turn on blinkers they work and brake lights work. All fuses are good. Ant thoughts or suggestions?

 

Pablo i could really use a diagram

 

There is a connector under the cab ....
Follor the cable ftom the trailerconnector in the back

 

I was having similar problems on two different trailers with the same truck and both times it was the trailer socket. There was a short (about 2 ft long) adapter from the socket to the wiring harness and both times in my case they (the adapter) were the problem.

 

Which relay was it. And what is its exact location. I have 2007 with identical problems .

 

Hello did you figure out the problem? I’m having trouble with the same problem?

 

Hey man did you figure out what was wrong? I’m having the same problem and can’t figure it out..

 

I know this is an old post , but my discovery might help someone. I have a 2007 Volvo VNL that driver kept blowing fuses. It started with one fuse a week and then it got more often and now as soon as you put a fuse in, it blows in your hand. I changed the cord to the trailer as well and programmed another LCM earlier and put it in, but that didn't fix it. Now that the problem is constant where I can shake some things around while fuses are blowing it would be easier to find it so that's what I did. I took apart some dash components, pulled up the fuse box and was yanking on a bunch of wiring. Then I found wire sparking when touching corner of metal, it rubbed through it. Volvo was bright enough not to put anything in between there. I shoved a rubber strip in there and zip tied it. Problem solved. Its under dash fuse box to the back right corner. Hope this helps someone save some $$$ and headache. I was blowing fuses #16 30Amp. Pics attached. Blessings, don't break down out there.